Expertflyer, a company that gives travelers information so that they can get the best possible airline tickets, is offering a free feature to travelers who want to change their seat or who are trying to get onto a sold out flight. To take advantage of the tool, called “Seat Alerts”, travelers create a free account on the ExpertFlyer website where they can setup an alert to be notified when the seat they want becomes available. This can be helpful for passengers who find themselves stuck with a ticket for the dreaded “middle seat” or who are having trouble getting onto a sold out flight.

Usually, airlines require flyers to have a ticket and will only change a passenger’s seat to another “unoccupied” seat. Travelers also usually have to wait until boarding time to find out if the seat they want becomes available. With “Seat Alerts”, travelers no longer have to wait and can switch their seat online once they receive a notification via text or e-mail.

The free feature allows travelers to maintain one active Seat Alert at a time. Additional alerts can be purchased for $0.99, and ExpertFlyer paid subscribers will be able to post several alerts at one time.